Transmissions



Aug. 15, 1961 o. K. KELLEY TRANSMISSIONS Original Filed Deo. 26, 1952 EN 7 'Y 8 Sheets-Sheet 1 Aug- 15, 1961 l o. K. KELLEY 2,995,955

@j B y orneys P, 64 /ggy Inventor O. K. KELLEY TRANSMISSIONS Aug. 15, 1961 8 Sheets-Sheet 3 Origlnal Filed Dec. 26, 1952 coNT/oL pk Ess URE PREssl/Qf Attorneys O. K. KELLEY TRANSMISSIONS Aug. 15, 1961 8 Sheets-Sheet 4 Original Filed Dec. 26, 1952 mVM. M. WW.

o. K. KELLEY' TRANSMIssIoNS Aug. 15, 1961 8 Sheets-Sheet 5 Original Filed Dec. 26, 1952 lk ka@ au I WWYM @/28 Attorneys O. K. KELLEY TRANSMISSIONS Aug. 15, 1961 Original Filed Dec. 26, 1952 8 Sheets-Sheet 6 O- K. KELLEY TRANSMISSIONS Aug. 15, 1961 8 Sheets-Sheet '7 Original Filed Dec. 26, 1952 1N VEN TOR @M1/@ A TTORIVE V ANN mwN,

8 Sheets-Sheet 8 O. K- KELLEY TRANSMISSIONS United States Pate-nti. M

2,995,955 TRANSMISSIONS Oliver K. Kelley, Bloomfield Hills, Mich., assignor' to General Motors "Corporation, Detroit, Mich., a corporation of Delaware Continuation of application Ser. No. 328,090, Dec. 26,

'1952. 'I'his application July 23, 1958, Ser. No. 750,848

37 Claims. (Cl. 74-677) This invention relates to hydrodynamic torque transmitting devices, particularly to converters which multiply torque and in which the positions of the blades of one or more of the rotating elements can be adjusted to control the transmission or multiplication of torquev While the basic three element hydraulic torque converter having blades at fixed angles has been successful and useful Within its inherent limitations and has provided reasonable eiiiciency over relatively short operating ranges of load and speed, and although some success has been had in increasing the ecient operating range through the addition of one or more turbine and reaction elements, inter-element clutching arrangements, refinements of blade design, etc., the attainment of maximum blade efficiency throughout the wide operational range required of automotive vehicles and the like has been prevented by the inability of the xed bladed elements to fully adapt themselves to the varying :duid ow conditions encountered. Also, blades, having xed angles cannot extend or adjust the range of torque multiplication which it is desirable to effect under different operating conditions. It is, accordingly, the principal object of the invention to overcome these disadvantages by providing a fluid torque transmitting device having blade adjusting means lin one or more ofits rotary elements and to provide means for controlling the blades in accordance with changes in speed and load demands on the transmission.

Another principal object of the invention is to provide such a transmission in which the blade shifting is effected by a power actuated member which controls the application of power to itself in response to the adjusted position of the blades.

As one example, which incorporates various aspects of the invention, an embodiment is described and shown comprising a hydraulic torque converter having an impeller, two turbines and a reaction or stator element in the uid circulating path. Certain features, however, of the individual blades elements, their relation to each other and to the transmission output shaft and their control means are applicable to hydrodynamic torque transmitting devices generally. Thus, the invention has among its other more specific objects to provide a hydraulic torque converter with adjustable reaction blades and/or adjustable turbine blades; to provide a transmission in which the torque delivered by the impeller is absorbed in varying proportions by two turbines in the fluid circulating path, with one of the turbines having blades variable in pitch with change in speed of the other turbine; to provide a transmission having an adjustable bladed tu rbine geared to the transmission output shaft through the output shaft driving connection of a fixed bladed turbine; and to provide a dual turbine transmission thus geared having means for controlling the gear drive ratio of an adjustable bladed turbine relative to that of a xed bladed turbine.

The means by which these and other objects of the invention are attained will be more readily understood from thoe following description of a preferred embodiment thereof, having reference to the drawings wherein:

FIGURES l and la collectively form a structural longitudinal section of a transmission embodying the features of the present invention, and showing the hydraulic 2,995,955A Patented Aug. 15, 1961 ICC torque converter and planetary gear train associated therewith.

FIGURE 2 is an enlarged fragmentary view similar to FIGURE l showing the turbine blade and stator blade vpitch controlling means in greater detail.

FIGURE 3 is an enlarged elevation of the valve body for the turbine blade pitch controlling means corresponding to the section shown in FIGURE 2.

FIGURE 4 is a sectional view of this valve body taken substantially on line 4-4 of FIGURE 3.

FIGURE 5 is a sectional View of this valve body take substantially on line 5-5 of FIGURE l2. l

FIGURE 6 is an end elevational view of this valve body taken from the right of FIGURE 3.

FIGURES 7, 8, 9, l0 and ll are sectional views taken substantially along similarly numbered lines of FIG- URE 3.

FIGURE l2 is an end elevational view of this valve body taken from the left of FIGURE 3.

FIGURE 13 is a fragmentary sectional view taken substantially on line 13-13 of FIGURE 2, showing further details of the stator blade adjusting means.

FIGURES 14, l5 and 16 are enlarged elevational views of one of the adjustable stator blades, with portions broken away and in section.

FIGURE 17 is a sectional view taken substantially on lines 17-17 of FIGURE 2 showing further details of the turbine blade shifting means.

FIGURE 18 is an exploded View showing the principal parts of the stator blade adjusting means in longitudinal Section.

FIGURE 19 is an exploded view of the turbine blade shifting means showing the principal paits in longitudinal section.

FIGURES 20, 21 and 22 are enlarged elevational views of one of the adjustable turbine blades with portions broken away and in section.

FIGURE 23 is a diagrammatic view of the blade seotions of the impeller, two turbines and the stator arranged in their respective relations to the directions of the converter fluid under different operating conditions of the transmission.

FIGURE 24 is a diagrammatic view of the transmission control system.

FIGURE 25 is a diagram of the transmission showing the relationship of the elements in one half of a generally symmetrical longitudinal section.

General.' arrangement Referring to FIGURES l and 25, a torque converter indicated generally by 1 is driven by an engine shaft 3 and drives a reduction gear unit 2 which drives an output shafto 6 which may be the propeller shaft of an automobile. The torque converter includes an impeller I driven by the engine, -a iirst turbine T-1, a second turbine T-2 and a reaction element or stator S. Turbine T-l is connected to a hollow shaft 49 which drives an input ring gear 204 forming part of a front planetary gear set including a reaction sun gear 203 and planetary gears 205 mounted on a carrier 206 connected to the output shaft 6. The reaction gear 203 can rotate forward, but is prevented from rotating backward by a ratchet device 217 when a forward drive torque establishing device 219-220 is set by any suitable hydraulic chamber 216.

Turbine T-Z drives an input ringe gear 207 larger in diameter than the ring gear 204 and forming part of a rear planetary gear set including an extension of the sun gear 203 and planetary gears 202 mounted on a carrier 211 connected to the outer race 213 of a one-way torque establishing device having a ratchet member 214 which prevents reverse rotation with respect to a stationary inner race 215 connected to the frame of the transmission. The ring gear 207 and second turbine T-2 are connected tov the front carrier 206 and therefore to the output shaft 6. Y Y

The -blades 42 of irst turbine T-l are mounted on pivots 43 so that the yblade angles can be changed by means of a rotary diaphragm 70 which can be rotated by la cam ring62 as will be explained. The blades 14S of the stator S are mounted on pivots 149 so that the blade angles can be adjusted by means of a cam ring 168 forming part of a hub which supports the stator for forward rotation, but only forward, about a stationary tube or ground sleeve 26. Reverse rotation of the stator is prevented by any suitable one-way device represented by the ratchet 157 between the hub and the ground sleeve.

YOperation of schematic arrangement Rotation of the impeller circulates liquid through the turbin and reaction member in the known manner to impress torque on the turbines. For low gear start and automatic two-stage drive, the cylinder 216 is vented to release the brake 219-220. On starting, torque is impressed simultaneously on T-l and T-2 but as `will be explained, higher torque is initially impressed on T41 than on T-2. This drives ring gear 204 yforward impressing forward torque on the carrier 206 and reverse torque on the sun gear 203. Because the carrier isA initially held'by the inertia `of the car, the sun gear rotating backward rotates the rear planets 202 forward and impresses yforward torque on the ring gear 207 and reverse torque on the carrier 211. The carrier is prevented from rotating backward by the one-way device 214 and tln's exerts forward torque o n the' ring gear '207 Because the rear ring gear 207 is larger in diameter than the front ring gear 205, the rear ring gear is turned forward by the sun gear 203 `at a speed reduction with respect to the sun gear which is greater than the speed multiplication from the front ring gear 20S to the sun gear. This alone tends to drive the output shaft at a slower speed than T-l or tends to multiply the torque of T-l. However, in addition, the forward rotation of the front carrier 206 (which is the fulcrum or reaction point in the backward drive of the sun gear 203 by T-1) reduces the speed of the sun gear which further reduces the speed of the output shaft and further multipliesthe torque of T-l transmitted to the output shaft. This compounds the two planetary gear sets and provides the lower of two possible ranges of speed ratios which is equivalent of the higher of two possible ranges of torque ratio.

Rotation of carrier 206 by the iirst turbine T-1 positively drives the second turbine T-Zand the ring gear 207 forward, which is permitted 'by the rear planetary gear set because the ratchet device 214 permits thecarrier 211 to rotate forward freely.

As car speed increases, hydraulic torque on T-1 progressively diminishes :and torque on T-2 progressively decreases and T-2 tends to increase in speed so that eventually it tends to rotate the carrier 206 faster than it is being rotated by the turbine T-1. When this occurs, the second turbine T-2 drives the output shaft 6 by direct connection through the carrier 206 due to hydraulic torque impressed on the turbine T-2 by the oil circulating by the impeller I. Rotation vof the carrier 206 faster than it can be driven by the turbine T-1 is permitted by the ratchet device 217. In order to start the car at a higher speed ratio and also to provide automatic two-stage dr-ive, the brake 219-220 is set. The rst turbine T-l drives the ring gear 204 forward and impresses reverse torque on the sun gear 203, but because the sun gear cannot rotate backwards, due to the one-way device 217 and the ybrake 219-220, this drives the carrier 206 and the output shaft 6 -for- Ward at -a speed ratio which is higher than the speed ratio of the two planetary gear sets compounded as described above. This also positively rotates the second turbine and ring gear 207 as described above which forward rotation is permitted by the ratchet device 214. When the speed of the second turbine tends to drive the carrier 206 faster than the first turbine can drive it, the second turbine takes over the drive as explained above and the first turbine freewheels, this freewheeling being permitted by the ratchet device 217.

The torque transmitting characteristics of the torque converter may be changed and particularly the range of torque multiplication may be increased by changing the positions of the movable blades 42 `and 14S as will be explained.

Representative structure FIGURES l and la show one form of actual structure of a transmission embodying the invention. Referring to these in detail, the transmission is shown as including a torque converter indicated generally `by the numeral 1 and a gear reduction unit indicated generally `by the numeral 2. At 3 is the end of rotary driving shaft such as a crankshaft of an automobile engine whose outer frame orhousing is partially shownat 4. The powerfrom the crankshaft is delivered through the torque converter 1 to the gear reduction unit 2, thence to the .transmission output shaft 6 which may be the propeller or drive shaft of the automobile. Y

The torque converter shown is a four-element multiple turbine type includingV a driving impeller I, rst and second turbines T1 and T-2, respectively, hydraulically driven by the impeller I, and a reaction-element or stator S. These converter elements are contained in a shell or housing 7, closed at its forward end by a cover 8 whose outer margin is bolted as at 9 and doweled as at 11 to a tlange provided on the shell 7. The outer edge of the torque converter cover 8 may be-provided `as sho-wn with external starting gear teeth; Compressed between the flanged end of the torque converter shell 7 and cover 8 is a neoprene O ring or other suitable gasket 15. The right end wall of the shell 7 is secured by rivets 13 to the hanged forward end of a pump drive sleeve 14 which extends rearwardly through the opening and is sealed by a packing element 16 to the fixed annular plate 17 which is bolted to the transmission outer casing 19 which connects at its front end to the engine housing 4 and has its rearward end enclosing the gear reduction unit 2.

The plate 17 forms lthe front and radially outer walls of housing for a pump indicated generally by the numeral 21, the rear wall of thehousing being an annular ring 22, generally L-shaped in radial section bolted to a fixed sleeve 26 extending concentrically through and radially spaced from the rotatable sleeveV 14. The pump 21 has a driving rotor 27 splined to sleeve 14 within the housing formed by the fixed plate 17 and fixed ring 22. The other constructional details of this pump 21 form no part of the instant invention, and may take various forms. Such other details of the pump 21 are ful-ly disclosed inthe U. S. Patent 2,805,628, Herndon et al., iiled April l, 1950, issued September l0, 1957. This pump draws the hydraulic uid from a suitable sump (not shown) and delivers it under pressure into the converter shell 7 through the annular clearance space 28 defined by the sleeves 14 vand 26. A fluid outlet path, to be later described, is provided for the return of the fluid from the converter to the sump, andby providing suitable pressure regulating means either in the pump 21 or in the returnpath the converted shell 7 is continuously maintained fullof ruid at substantially constant pressure during engine operation.

The converter shell 7 and cover 8 are supported and driven yby the engine crankshaft 3 through a boss 29 in a recess in the rear end face of the crankshaft, and a spider having its hub 31 bolted and doweled to the crankshaft and its arms 32 secured at their outer ends to the converter cover 8 by the bolts 9.A

The impeller I, comprising vanes or blades 36 secured escasas b between an inner shroud 37 and an outer shell :38, is con nected to rotate with the shell 7 as by a plurality of radiating straps, one of which is shown at 39, welded or otherwise fixed to the impeller outer shell 38 and attached as by the rivets 13 securing the shell 7 to the sleeve 14.

The blades 42 of turbine T-l are pivotally supported for angular adjustment about axes substantially parallel to and adjacent their leading edges by journalling pins 43 which are secured at their opposite ends in inner and outer members 44 and 46. The outer shell 46 of T-l extends forwardly and is splined at its front end to the outer peripheral edge of a driving disk 47 which is secured as by bolts 48 to a driving ange 45 on the forward end of an inner torque transmitting shaft or tube 49. The shaft 49 is one of the output or driven shafts of the torque converter and is one of the driving shafts or input shafts of the gearing 2. The rearwardly extending tabs 51 which are bent down in forming the inter-spline recesses of the disk 47, have a close fit in the outer member 46. At 52 is an outwardly expanding snap ring which abuts the front face of the disk 47, maintaining the splines of this disk -fully seated in the inter-spline recesses of the outer member 46, and engages inwardly presenting grooves provided in the splines 53 of the member 46.

As best shown in FIGURE 2, a radial and thrust bearing. 57 vis mounted between the converter cover 8 and the T-l drive disk 47.

Rotatably and slidably fitting inside the T-l turbine outer shell 50 is a control ring 59 (FIGURE l) having holes 58 in which are journalled projections 61 on the outer ends of the blades 42 to maintain the angular positions of the `blades 42. Rotation of the control ring 59 Irelative to the turbine shell changes the angles of the blades. The -fforward end of the control ring 59 is riveted to a torsionally stii lbut axially resilient corrugated diaphragm 70, the center of which is fixed to a turbine control cylinder 62 which slides on drive flange 45 which also forms a piston.

As best shown in yFIGURES 2, 17 and 19, this cylinder 62 has a Ibore 63 slidably fitting on a valve housing 64 formed integral with the driving flange 45 and shaft 49. The cylinder side wall 66 can slide and rotate with respect to piston 45 which is fitted with a pressure sealing ring 67. A forwardly presenting annular recess 68 is provided in the cylinder end wall, into which extends a cam ring 69 fixed to the driving flange 45 by the bolts 48. A plurality of circumferentially spaced helical cam slots 72 are formed in the cam-ring for rollers 73 which are journalled on pins 74 in the cylinder 62. A seal ring 76 (FIGURE 2) is mounted in an external groove on the outer periphery of the valve housing 64 for sealing engagement with the cylinder end -bore 63. This provides an expansible hydraulic chamber 76a for controlling they pitch of T-l blades. When the chamber is supplied with oil under pressure it moves the cylinder 62 to the right as FIG. 1 is seen, against the pressure in the converter chamber, to rotate the cylinder 62 and control ring 70 and increase the angle of the T-1 blades by moving them toward the position 4 shown in FIG. 23.

y The valve housing 64 has an opening 78 adjacent its forward end which connects hydraulically with control chamber 76a through slot 80 in -ange 45 and annular groove 79 formed in the end wall of the cylinder 62 to establish communication 'between the valve housing and the control chamber 76a. Secured in the tube enlargement 64 is a bushing forming a turbine control valve body 81, shown in detail in FIGURES 3 and 4. Fitted into its open rear end is a fluid supply pipe 84 which extends concentrically through the drive shaft 49 and makes a uid connection with the interior of the hollow output shaft 6 (FIG. l). T-l blade control fluid, for supply to chamber 76a which may be introduced by any suitable means (not shown) to the interior of the hollow output shaft, is thus conducted to the rear end of the valve body 81 separately from the converter iluid conducted into.the con# verter shell through the pump discharge space 28. Any suitable means of sucient capacity and pressure, such as the pump 21, may be employed as the source of this separately conducted T-1 control Huid, and in FIGURE 24 to be later described there is illustrated a control system for regulating the pressure at which this T-l control uid is maintained in the output shaft in accordance with the output torque and speed demands on the transmission. Since their functions and operating pressures diier from each other these fluids will be distinguished hereinafter in the description by designating that which enters the Valve body from the pipe 84 as the turbine-control-uid, and that which is conducted by the annular space 28 to the converter shell as the convertenuid. The space 109 between pipe 84 and the inner driving tube 49 serves as a return passage for conducting to the transmission sump the turbine-control-uid when it is exhausted or vented from the chamber 76a. The connection of the pipe 84 to the output shaft may be made, as shown in FIGURE l, in the form of a ferrule 86 fixed to the rear end of the pipe 84 and extending into a counterbore in the forward end of the output shaft 6. A suitable seal 87 in the form of an O-ring of neoprene or the like is provided which is retained in a groove about the periphery of the ferrule 86 for engagement with the output shaft counterbore.

Fixed to the cylinder 62 as by bolrting at 88 is a valvebiasing spring housing support in the form of a `bracket y89 supporting a cup-shaped spring housing 9.1 disposed in the torque converter cover 47. Seated in this cup are two helical compression springs 94 and 96 whose rear ends abut a hat-shaped retainer 97 which bears against a push rod 98 which urges the valve 99 remardly. Rearward travel of the spring retainer 97 is limited by a pair of diametrically spaced abutment pads 100 formed integrally of the valve body, as best shown in FIGURES 4 and 12.

The valve 99 is of the spool type, having the front and rear pistons or lands 101 and 102 separated by a groovev and interconnected by a stem 103. 'Ihe valve 99 when open, that is, placed toward the left as FIG. 2 is seen, connects the T-1 control cylinder 76a to a source of oil under variable pressure, which tends to increase the angle of the 'IL-1 blades, and when closed, that is, placed to the right -as FIG. 2 -is seen, vents the control cylinder, which decreases the angle of the blades, as Will be eX- plained. The springs 94 and 96 and the pressure in the converter constantly urge the valve closed to decrease the angle ofthe T-1 blades, and the force of the springs increases as the angle of the blades increases due to movement of the cylinder 66 on which the springs are supported. The control pressure, when admitted to the face of the land 102 urges the valve open 'to increase the angle of the blades. The force of the springs 94 and 96 normally holds the valve closed with its rear end against a snap ring v104 in an internal groove 105 (FIG-y ure 4) in the valve body.

The valve 99 serves to meter the flow of turbinecon trol-duid from lthe pipe 84 through the valve body to the control chamber 76a. To provide separate passageways for the control and converter fluids into and out of the valve ibody bushing, its internal and external surfaces are shaped as -best shown in FIGURES 3-l2. At its rear end, as will be seen from FIGURE 6, the outer surface of the valve body has a longitudinally extending keyway 106 and a longitudinally extending turbine-control-fluid vent slot 107, the bottom rear extremity of the latter being chamfered as at 108 (FIGURES 4 and 6) to pro? vide a conduit to the return passage 109 (FIGURE 2) `between the pipe 84 and the tube 49. Keyway 106 engages a projection 106a (FIGURE 6) provided on the Valve housing 64 to maintain the valve body in its proper angular relation with the tube 49. The slot 107 extends forwardly to connect with a radial exhaust or vent port 111 (FIGURE 4) cut through thev side wall ofthe valve body and connecting with lan internal annular vent groove 1'12V in the valve body. Formed in the external surface of the valve body -forward of the slot 107 is a longitudinally extending converter pressure supply groove 113 (FIG. 3) which is connected to the forward end of the valve body bore in front of valve land 101 by a hole 114. .The rear end of the groove 113 registers with a converter pressure supply hole 116 (indicated in broken outline in FIGS. 2, 3 and 4) extending through the wall of the valve housing l64, and 4into the working space of the torque converter, whereby the front face of the front piston end 101 of the valve 99 is subjected at all times to converter-huid pressure. Behind the annular vent 'groove ,112, as 'shown in FIGURE 5, the valve body bore has anv annular turbine-control pressure supply groove 117 which is connected by a radial port 118 to a groove 119 extending Aforwardly lalong the outer surface of the valve body to a control pressure inlet port 121. The latter port, in turn, leads inwardly through the valve body side wall to an annular inlet groove 122 in the bore of the valve body just vback of the converter-Huid passage114. Between `this last mentioned inlet groove 1722 and the vent groove 1112 which connects with the turbinecontrol-fluid return slot v107, the valve body bore has a control cylinder port 123 which leads radially outward to an external longitudinal groove 124 (FIGS. 3, 5, 9) ex- Itending forwardly along the valve body outer periphery and communicating -With the opening 78 in the valve housing 64 (FIGURE 2) which leads to the control chamber 76a.. The widths of the annular grooves 112, 117 and 122 and their axial lspacing relative to each other, are so dimensioned with'reference to the lengthsV and axial spacing of fthe valve piston ends 101 and 102 Ithat as the valveis moved forwardly from its closed position of abutment with the stop ring A104 the rear annular supply groove 117 will be uncovered rst by land .102, followed by covering of the exhaust or vent groove 112 by land 102 slightly in advance of the uncovering 0f the front inlet groove 122 by Iland 101. As aV result, the pressure of the turbine-control-uid acting-on the .front faces of 'the'cylinder 62 is at all times directly responsive to the pressure in the supply pipe y84.

It wiillthus be seen that when turbine-control-uid is introduced at suflicient pressure to the interior of the output shaft, this pressure acting against the rear face of the valve rear piston 102 causes the valve -to `open by moving forward against the biasing force of the springs 94 and 96 to connect the inlet port 121 to the cylinder 76a `and close the exhaust port 111 to let fluid ow from the supply pipe 84 through the valve body to the front facesvof the cylinder 62. rThis pushes the cylinder 62 rearwardly and (by reason of the camming action of the f rollers 73 in the helical slots 72) rotates it in a clockwise direction (as viewed in FIG. 17 or from the right of FIGURE l) relative to the driving disk 47 and the core members 44 and 46 of the turbine T-1.v This is represented by the arrow in FIG. 17 and by the symbols 126 and 128 in FIGURE 23. Symbol 126 represents the View of the feathers of an arrow flying directly away from the observer which indicates that the part adjacent the symbol is moving away from the observer toward the space behind the plane of the paper of FIGURE 19. Symbol 128 represents the view of the point of an arrow ying directly toward the observer and indicates that the part adjacent the symbol is moving toward the observer, that is toward the space in frontof the plane of the paper. Either of the symbols, or the two together, represent that the entire cylinder 62 is rotating clockwise, as viewed from the right of FIGURE 19, relative to the element of reference, which is the driving disc 47. Rotation of the cylinder 62 in this direction relative to the core members 44 and 46 is, in turn, transmitted through the diaphragm 70 to the control ring 59, causing the blades 42 to pivot in a counterclockwise direction as viewed in FIGURE 23 from' their low angle settingY shown in solid lines-toward a maximum angle setting indicated by the broken' outline 42". The rearward movement of the bracket 89 and spring housing 91 with the cylinder causes the springs 94 and 96 to increase the biasing force on the valve, which urges the valve toward closed position with increased force. Thus the valve is kept balanced by the pressure in one direction of the turbine-control-fluid acting on the rear face of the valve rear piston end 102 and the force of the converter pressure and the force of the springs 94 and 96 in the opposite direction. For any selected turbine-control-fluid pressure therefore, there exists a corresponding stabilized angular setting of the T-l turbine blades 42.

Also acting against the rear faces of the cylinder 62, in vopposition to its rearward movement in response to the turbine-control-fluid pressure as just described, is Ithe pressure of the converter-Huid within the shell 7 and cover 8. Compensating at least in part vfor this converter-duid pressure eect on the cylinder 62, and also serving to neutralize or substantially neutralize changes therein, is the force exerted by the converter-fluid pressure on the front face of the valve front piston end 101. Subjection of this face of `the valve to the converter tluid pressure is constantly effected through the passages 116, 113 and 114 as previously described.

The blades (FIGURES l and 2) of the second turbine T-2 are rigidly interconnected by inner and outer members, similar in manner to the blades 36 of the impeller I. The outer member of this turbine terminates in a radially inwardly extending web portion 131 which is riveted to the driving flange 133 of an ou-ter tube 134. The tube 134 is the second output or driven shaft of the torque converter and is also the second input or driving shaft for the gearing. Adjacent its ange 133 this tube has an enlargement 135 which encompasses the rear portion of the inner tube enlargement 64 and is rotatably journalled thereon by a sleeve-like bearing 136, Forwardly of the outer driving tube flange 133 is a thrust ring 137 encircling and splined to the inner tube enlargement 64, and between the ilange 133 and the thrust ring 137 is a thrust bearing washer. The thrust ring 137 is located against forward displacement by a snap ring mounted in an annular groove provided in the externally splined section of the inner tube enlargement 64. The rear face of the outer tube ange 133 bears against a thrust washer which separates and accommodates relative rotation between this flange and the hub 141 of the stator S.

The outer tube 134 has its internal diameter sufficiently larger than the otuside diameter of the inner tube 49 to provide an annular space 142 ltherebetween which serves as a return passageway for the converter-fluid flowing from the torque converter. Connecting passages 191, 192 and 193 (FIGURE l) lead out from the rear end of this space 142 through the outer tube 134, fixed sleeve 26 and pump cover 22, respectively, to the sump via suitable cooling means (not shown). Converter-fluid leaving the converter ows to this annular space 142 through ports 143 and 144 provided in the outer tube enlargement 135 and stator hub 141, as shown. Continuous communication between these ports is effected by an annular groove 145 provided on the inner periphery of the hub 141, and the rfront face of the latter is annularly grooved at 146 to conduct the `converter fluid from the space 147 between the blades 130' of the second turbine T-2 and the blades 148 of the stator S.

' The reaction blades 148 are pivotally supported for angular adjustment about axes substantially parallel to and adjacent their leading edges by pins 149 which are secured at their opposite ends in the hub 141 and inner member 151, in a manner generally similar to the angularly adjustable blades 42 of the rst turbine T-l. The hub is generally annular and has its radially innermost cylindrical wall 152 fixed to the outer race 156 of a oneway brakeof conventional design having rollers or sprags 157 (FIGURE 1) which prevent backward rotation of the stator with reference to the xed sleeve. Also mounted to rotate with the stator hub 141 and brake race 156 is a rear thrust ring 158 which bears on a bearing washer seated against the anged front end of the pump drive sleeve 14. This rear thrust ring is provided with connecting drilled recesses 161 and 162 through which the converter-huid ilowing through the annular clearance space 28 from the pump 21 may enter the interior of the converter shell 7.

The radially outermost cylindrical wall 163 of the stator hub 141 is formed with a cylindrical external surface for rotatably supporting a stator blade control ring 164 having radially extending holes 166 (FIGURE 18) therein adjacent its forward end which receive projections 167 on the outer ends of the stator blades. The rear end of this member 164 is provided with a plurality of circumferentially spaced helical slots 168 (best shown in FIGURE 18) into which extend the ball ends of studs 169 whose shanks are suitably journalled and retained end-wise in needle bearings 171 pressed into recesses provided therefor in the outer periphery of an annular piston 172. The walls 152 and 163 of the hub 141 define an annular cylinder for the piston. Dowels 173 extending into drilled recesses in the front face of the piston and anchored as by screws 174 to the web of the hub 141 serve to slidably support the piston 172 and prevent its rotation relative to this hub. Suitable packing rings 176 and 177 are mounted on the outer periphery of the piston adjacent its front end and on the outer periphery of the clutch race 156 just forward of the rear end of the piston, as shown in FIGURE 2, to effect a fluid tight seal. Provision is made for introducing hydraulic lluid under pressure to the front end of the piston by forming the front face of the latter with an annular relief groove 178 which connects with an annular clearance space 179 between the piston and the inner wall `152 of the core member, which latter clearance space, in turn, is connected by one or more radial slots 181 (FIG. 2) cut in the rear face of the inner wall 152 to the annular clearance space 182 between the sleeves 24 and 26. Entrance of the hydraulic fluid to this inter-sleeve space 182 is effected through passage 183 (FIGURE l) leading to the rear end thereof through the iixed sleeve 26 and pump cover 22, The pump 21 may also serve as the source of this lluid which will hereinafter be designated the stator-control-uid, and in FIGURE 24 to be later described there is illustrated a suitable means for controlling the admission of this fluid to the passage 183 in accordance with the output torque and speed demands on the transmission.

By reason of the directional pitch of the helical cam slots 168, (FIG. 18) rearward movement of the piston 172 in response to stator-control-fiuid pressure applied to the front face of this piston eiects rotation of the control ring 164 in a clockwise direction (as viewed in FIG- URE 13) relative to the core member 141, causing the stator blades 148 to pivot from their low angle setting shown in solid lines in FIGURE 23 to the high angle setting shown in broken outline in the latter iigure. Opposing such rearward movement of the piston 172 is the force of the converter-duid pressure acting against the rear face of the piston, and this latter force is suicient to maintain the piston in its Aforward or low angle blade position (shown in FIGURES l and 2) except when the stator-control-uid pressure is applied.

The term low angle, as used herein, means that the general direction of the blade makes a small angle with respect to the plane determined by the principal axis of the transmission and the pivot or leading edge of the blade, as is the case with the solid line position of blades 42 and 148 in FIGURE 23. With a blade at high angle the general direction of the blade makes a large angle with respect to this radial-axial plane, as illustrated in the dotted line positions of blades 42 and 148 in FIG- URl-ll 23.

As is known in the art, blades at low angle change the direction of oil relatively little, and so eect a relatively low torque multiplica-tion, whereas blades at high angle change through a relatively large angle the direction of the oil between its absolute direction when it strikes the blade, and its absolute direction when it leaves the blade. This produces a relatively large torque multiplication in the converter. The terms low angle and high angle may be considered to be the opposites or complements of the terms low pitch and high pitch in the sense these latter terms are used in the screw thread and propeller arts.

From the description Ithus far given it will be seen that by reason of the inner and outer tubes 49 and 134 being rigidly connected to the first `and second turbines T-l and T-2, respectively, they each tend to rotate counterclockwise (as viewed from the right of FIGURE l and indicated by the arrow 197 in FIGURE 23) in response to rotation of the converter-huid in that direction with the impeller I and the engine crankshaft 3. As is the case with conventional torque converters, the converter-duid has a toroidal direction of ow indicated by the arrow 41 (FIGURES l and 23) Vin Iaddition to its rotational movement with the impeller about the axis of the transmission, and the velocity of the toroidal relative to the rotational movement of the converter-duid increases and decreases with increase and `decrease in rotating speed of the impeller relative to the turbines. Also, the stator blades serve in conventional manner to multiply torque by redirecting the converter-Huid to enter the impeller in the counterclockwise direction. The one-way brake 156-157-26 eiects this result by preventing the stator from rotating clockwise during the multiplication but permitting the stator to rotate counterclockwise when the fluid ows from the turbine in such direction that it strikes the backs (convex sides) of the stator blades. l

The -irst and second turbines T-1 and T-2 may have ltheir tubes 49 and 134 geared at relatively high and low torque ratios, respectively (as provided for example, in the gear reduction unit 2, to be later described), to the transmission output shaft 6. At stall, i.e., with the engine running and both turbines T-l and T-2 held stationary by the output load on the transmission, the ratio of toroidal to rotational ow of the converter-duid produced by the rotation of the impeller is at a maximum. When the car begins to move and as the speeds of the turbines T-l and T-2 increase relative to that of the impeller, the toroidal flow decreases and the rotational speed of the converter-uid increases.

The torque absorbed by the turbines in response to impeller rotation is dependent on the relative speed of the impeller and turbine and the angular relation of the blades of the respective turbines to the direction of the converteruid entering the turbines. This torque is referred to as the stall torque when it just equals the torque input from the impeller and is insufcient to overcome the output load resisting turbine rotation. The ratio of the impeller input torque to the stall torqueor stall torque ratio- :must therefore exceed unity under all operating conditions that require driving the transmission output shaft. By varying the pitch of the turbine T-1 blades, in accordance with the invention, it is possible to vary the `stall -torque ratio to meet different output requirements of the transmission. Thus as applied to automotive vehicle operation, for example, the turbine T-1 blades may be set atan intermediate-angle (such as indicated by the broken outline 42' in FIGURE 23) during the initial acceleration, and as the vehicle increases in forward speed with resultant decrease in the stall torque ratio required, the angle of the T-1 blades can be increased as necessary to obtain the desired rate of vehicle acceleration.

During engine idling, the -lrst turbine blades 42 may be set at la maximum angle setting such as indicated by ethe broken outline 42 in FIGURE 23. In this position -as is known in the art, the blade 42 tends to restrict the volume of oil which can flow through the converter, and

" the relatively small amount of energy in the converter- 11 desirable. result that tendens@ 9i the Vehicle t0 steel? at'ensne idle. ere'mlimized! it conceivably might be preferable for utmost eiieny and reforman?? that the Stetb blade ale'b? .varied gradually between minimum and maximum Settings. satisfactory results have been obtained with the simpler onstruction and control which provides for the stator blades having only the alternative jlow angle and high angle settings such as are indicated Vin solid and broken lines respectively in FIGURE 23. With this arrangement, the low angle setting has been found to give Vsatis- .favtory Performance @der all @naine Operating. Condif tions -above idle and at less than -full throttle, and also during full throttle road load or cruising operation when it is `desired that the torgue converter operate simply as a fluid coupling. The high angle setting may, therefore, be reserved vonly for use obtaining maximum acceleravtion at -full engine throttle, up to a predetermined cruising .speed and for engine idle operation, yin which latter in- ,stance it serves to impede toroidal flow of the converterhuid vand thereby reduces .vehicle creep.

Gearing As shown on FIGURES 1 and lq, the gear reduction unit 2 includes compoundable planetary gear sets 201 and 202 having a vcommon sun gear 203 journalled on the Ltransmission voutput shaft 6. The front planetary set 201 has an `annulus gear 204 splined as shown to the first turbine tube 49 ,and rneshing'with planetgears 205 which in turn mesh with the sun gear 203 and are mounted on a .carrier 206 which is `splined Vto the output shaft Y6. The annulus gear 207 of the second or `rear planetary set is 4shown `as formed integrally with the front planet carrier lG-.and is ldirectly coupled as by splining at 208`t'othe second turbine T'-,2 by'a coupling member 209 splined to the outer tube 13,4. Meshing With Ythe rear annulus gear 207 are ,a plurality of planet gears 210 which also vvrneslrwith the sun gear 203, and have their carrier 211 .directly coupled as by pins 212 tothe ,outer race 213 ,of -anover-running brakeof conventional form having rollers or sprags214 and Van inner race 215 to the transmission housing 19. The over-running brake 213, 214, -215 perrnits Vforward rotation ofthe second planetary carrier 211 lbut prevents reverse rotation. Adjacentits rearward/end the sun gear 203 forms the inner Yrace `of a second'poverrunning brake having rollers orsprags 217 and an outer race V218 which can beheld fast by afluid pressure con- .trolled brake. Asshown, this fluid pressure controlled brakecomprises aplurality of xed disks 219 splined to the fixed cylinder 216 and arranged for lfrictional .engagement with a plurality of Vdriven disks 220 splined .to the .outer race 218. Arrangedwithin the cylinder 216 is'a .piston 221 which is urged rearwardly out of clamping engagement with the disks 219 and 220 by a spring 222, but can be moved in theopposite direction in response to lfluid pressure within .the cylinder 216 to clamp Vthe disks ,together `and thereby lock the outer race 218 against rotation in either Adirection relative to the housing'19. When theouter race 218 is thus locked against rotation the sprags 217 permit Vforward rotation of the suny gear but prevent reverse rotation. Suitable communicating -passages 223 and 224 are provided in the housing 19 and cylinder 216 for admission of the yiluidto actuate the piston 221.

With the fluid pressure controlled brake 219, 220disrengaged andthe vehicle at rest, rotation ofthe first turbine T-l is transmitted Vto-the output shaft 6 through thean- -nulus gear '204, first planet gears 205,*sun gear V203, second planet gears-2104and finally` the second vannulus gear 207. During this drive .the fluid pressurecontrol brake 2 1,922 0 is ,disengaged, allowing the sun gear-,2,03 to Vro,- tate clockwise, anda high kratio of turbine T1 speed to Vturbine 17T-2 speed is permitted. Whilethepturbine T -2 may'rotate ,at Ya greater Yspeed in proportion to Vthat lof the turbine Tf1 than is permitted by this ratio, their geared relationship prevents the turbine T-2 from r6- fating at a slower speedl relative toV that of the turbine T1. With increase in speed of the turbine T-2 relative to that of turbine T-1 due to increase in speed of the output shaft which results from reduction of the load as the car accelerates, the over-running brake 213, 214 allows the carrier 211 to vfreewheel and the second turbine T-2 drives the car alone, as is known in the art, and as ex# plained, for example, in my U.S. Patent 2,803,974 issued August 27, 1957, on an application filed July 31, 1948. When the uid pressure controlled brake 219, 220 is applied (stopping the sun gear 203 from rotating backward), the rotation of the turbine T1 provides a single reduction drive of the output shaft through the firstannulus gear 204, planet gears 205 and planet Ycarrier 206 the sun Y203 being the reaction gear. Torque is also transmitted through the second Yannulus gear 207 and coupling member 209 to the second turbine T-2. When this drive is in' eiect the rear carrier 211 freewheels forward, the rear planetary gearset being inactive. The speed ratio between the first turbine T-l and the output shaft is the higher of the two possible ratios, that is the torque multiplication is the lower. As with the low speed drive,thrje vturbine T-,2 may approach the speed of the turbine Tf1, this being permitted by the over-running brake 217, 21S allowing Vthe sun gear y203 to freewheel in the counterclockwise direction.

Inv both high speed and low speed drives, any increase in the speed ratio of the second turbine relative to that of the first turbine T1 beyond the speed ratio of the gearsets Vresults in the turbine T-l discontinuing to transmit driving effort 4tothe output shaft 6 and merely being carried in the converter-huid passing between the impeller I and the turbine T-2. By increasing the pitch tof the turbine T'-1 Yblades 42 in accordance with increasing speed of the output shaft I6, however, the rotating speed of the turbine T41 relative to that of turbine T-2 can be mainf tained at the ratio determined by the particular gear setting and the'frst turbine can continue to transmit torque.

Control Referring now to FIGURE 24, there is diagrammatically shown a suitable control system wherein hydraulic fluid delivered fnom the pump 21 may be applied to control the blade pitch of the turbine T1 and stator S, and the gear ratio of the reduction gear unit 2. As indicated in the lower right hand corner of FIGURE 24, the pump 21 yreceives fiuid from .the sump and discharges it through a main pressure line 221, to which is connected theconverter shell 7 by a branch line havinga flow reducing restriction 222. In the fluid return line from the converter is al conventional spring biased pressure relief valve v22.3 controlling ports 224 and 225 leading respectively to the sump and' to the lubricating passages in thetransmission via passage 226 in which the pressure may be regulated to a further reduced value as by`a conventionalspring loaded relief valve 227. This maintains a substantially constant pressure, below main line pressure, in the converter. i In the upper left hand corner vof FIGURE 24 is'shown a throttle-pressure valve in the form of a self-regulating piston type metering valve 22S slidably in a valve body 229. This valve 228 has spaced apart lands 230 and 231 and a piston 232. Art 233 is indicated a manually controlled member whose position is responsive to throttle opening'of the engine and which has a fixed pivot 234 about which it is movable with movement lof the engine accelerator or other speed `control regulator (not shown) from a minimum speed setting (idling) position shown in FIG. 24 toward the right to a maximum speed setting (above full throttle) position to apply increased biasing force to the valve 22S through a spring 239. The expres# sion above full throttle as used herein and usually in the art means that the mechanism has fully opened the throttle, and has movedV farther, without aifecting throttle opening, to accomplish some other control function, as will be apparent from the explanation below. Movement of the throttle-pressure valve 228 to the right from its position shown operates to open main line 221 at land 231 and admit uid from the main line 221 into a regulated pressure chamber connected to a metered pressure line 240 and movement to the left discharges uid from the line 240 to the sump by the vent port EX, Opposing opening movement of the valve 228 is the metered line pressure acting at the right of land 231 by reason of the bleed passage 241 connecting the opposite ends of the land. Also acting in opposition to the biasing force of the spring 239 is the governor controlled pressure in the line 242 acting against the right hand end of the piston portion 232. `Consequently the throttle pressure valve maintains a pressure in the throttle pressure line 240 which increases with increasing torque demand on the engine as indicated by amount of throttle opening. The throttle pressure also decreases with increasing speed of the car, as indicated by increasing governor pressure in line 242, as will be explained.

I'he governor controlled pressure in the line 242 is regulated by a conventional governor indicated at 243 rotated at a speed which is responsive to transmission output shaft speed and exerts a force, measured by car speed, on a second self-registering valve 244. With increase in output shaft speed the governor moves the valve 244 to the left from its position shown to increase the pressure in line 242 by admitting additional duid thereinto from the main pressure line 221. Movement of valve 244 to the left uncovers the port connected to line 221 so that oil underv pump pressure in this line entersl the valve body between two piston-like end parts of valve 244. Such oil can pass through the orifice indicated by dotted lines in the left-hand piston part and continue into line 242, to be routed to various parts of the system. When the pressure in these parts develops to such an extent as to be applied to the left end of valve 244 with suflicient force to overcome the force of governor member 243, valve 244 is moved to the right, uncovering the exhaust port and permitting some of the oil in the developed head to be exhausted. This metering action continues with the result that as the member 243 increases the force moving valve 244 to the left, the resultant pressure head developed in line 242 and its connected parts increases, since higher pressure is required to move the valve 244 to the right against the action of the governor. The maximum pressure head developed cannot exceed the pressure of the pump 21.

At 246 is shown a turbine control valve in the form of a self-regulating valve which controls the pressure in the pipe 84 and turbine control chamber 76a by regulating the admission of fluid from the main pressure line 221 into the line 245 leading to supply pipe 84 (FIGURES 1 and 2). YIn the idling position of this valve 246, as shown, full main line pressure is delivered through the line 245, holding the T-l turbine blades in their maximum angle position. Above idling speed, this valve 246 is sensitive to both governor controlled pressure in line 242 on piston 286 and throttle line pressure in line 240, from valve 228 on piston 274, both tending to increase the pressure of the turbine-control-uid to increase the angle of the T-l blades, with the force of the governor controlled pressure being applied directly thereto and that of the metered main line pressure being applied through a spring 247.

" At 248 is shown a gear shift valve in the form of a spring biased normally closed valve which controls the admission of main line pressure to the line 249 to operate the brake piston 221 (FIGURE la) for locking the sun gear 203 in eiecting a low torque multiplication in the gearset. The valve 248 is urged to open position against the closing force of its spring 250 by throttle pressure in the passage 240 and also by the governor pressure in the line 242, the force of the latter pressure being transmitted to the valve 248 through a spring 251 by a piston 252 whose' movement in the opening direction of the valve 248l is .limited by a stop shoulder indicated at 253.

When the gear shift valve 248 is opened, main line pressure (from line 221) is applied to the cylinder 216 (FIGURE la) and is also applied through the passage 249 to a small diameter piston portion 254 provided on the left hand end of the turbine control valve 246, with the result that the eiective closing force acting on the valve 246 is increased, causing a reduction in the turbinecontrol-huid pressure (line 245) and consequent establishment of the turbine T-1 blades in a lower angle simultaneously With the establishment of high-speed ratio in the gearset. The areas of the uid pressure operating surfaces on the valves 246 and 248 and the biasing forces of the springs 247, 250 and 251 are so selected that upon movement of the manually controlled throttle member 233 from its minimum speed setting to its maximum speed setting, the force of the governor controlled pressure in the 'line 24-2 acting on piston 252 and on piston portion 286, plus the force of the metered main line pressure in the passage 240 applied to piston 274 to assist spring 247, on the valve 246 is suicient to provide a turbine-controluid pressure eiective to position the turbine T-l blades in an intermediate angle setting such as is represented by the broken outline 42 in FIGURE 23. As the governor controlled pressure increases with increase in output shaft speed, the turbine-control-fluid pressure increases accordingly to advance the blades 42 to their maximum angle position (shown in broken outline 42 of FIGURE 23). Thus, with the throttle held in its maximum speed position, the blades 42 are initially advanced to their intermediate angle, from which they further advance toward their maximum angle as the speed of the output shaft increases. Then, when the force of the governor controlled pressure applied to piston 25-2 and acting through the spring 251 reaches a suflicientlly high value that its force (plus the force of the metered main line pressure) is suilicient to open the valve 248 and thereby cause the gear ratio to change from its high torque ratio to low torque ratio, the added closing force applied to the piston portion 254 by the main line pressure supplied by pressure supplied by line 249 effects a sufficient reduction in the turbine-control-tluid pressure that the turbine T -1 blades return to their intermediate angle. Without changing of the maximum speed setting of the manually controlled lever 233, the governor controlled pressure in line 242 will then continue to increase with still further increase in output shaft speed, resulting in the turbinecontrol-fluid pressure again building up and gradually returning the turbine T-1 blades to their maximum angle.

At 260 is shown a spring-opened valve which controls the application of main line pressure from the passage 221 to actuate the stator control piston 17-2 and thereby effect pivotal movement of the stator blades 148 from their low angle position shown in solid lines in FIGURE 23 to their high angle position shown in broken outline in FIGURE 23. Since it is desired that the stator blades be maintained in their low angle position during part throttle operation corresponding to intermediate positions of the manually controlled lever 233, suitable means is provided for effecting this result. As shown in FIG- URE 24, a Vso-called detent or follower valve 261 is provided vwhich is linked to move with the manually controlled lever 233 to admit main line pressure from the passage 221 into -a branch passage 262 for application through the connecting passage 280 against the valve 260 in the direction to close oli the ilow of main line pressure to the stator piston 172. In the initial position of the follower valve 261 as shown, corresponding to the minimum speed of the lever 233, no such closing force is applied to the valve 260, and hence it remains in its open position as shown and maintains the stator in high angle. Upon initial movement of the lever 233 from its minimum speed setting, however, the follower valve 261 moves to the right and connects the branch passage 262 to the main :line pressure in passage 221 so that mainline pressure Vin passage i280 closes the valve 260 against the force of the Ispring277. The lmain line pressure then existing in the branch passage 262 and on the right of piston 263 is etective to maintain piston 263 in abutment with a stop, represented by the shoulder 264, the left 'side of the pistonV being vented by the port EX. In this position the piston 263 resists movement of the manual lever 233 beyond its full throttle position with -a force measured by main line pressure. This resisting action occurs just prior to the piston portions 265 and 266 of the 'follower valve interrupting communication ybetween main line 221 and the branch passage 262 and establishing communication between main line 221 and a second branch passage 267. Upon applying the necessary additional force to displace the piston from its shoulder 264, main line `pressure is admitted to the second branch passage 267 and acts `against the piston 281 which then `drives the valve 260 to its open position shown and 'main line pressure is again applied to stator piston 172, causing the stator blades 148 to move to their high angle setting shown in broken outline in FIGURE 23. As is known in the art, this increases the torque multiplication of the torque converter in response to an increase in torque demand on the engine.

'Ihe large piston portion 268 of the stator control valve 260 is subject at all times to the governor controlled pressure, tending to close this valve and thereby cause the 'stator blades to assume their low angle setting. The. area ofthe piston portion 268 against which the governor controlled pressure acts is made suiciently large that the governor controlled pressure will be eiective both to prevent this valve frorn opening and thus maintain low stator angle in the event the throttle is olosed while the output shaft is rotating at substantial speed, and to return this valve to closed position, and restore low angle ras the output shaft reaches `a predetermined high speed 'after it has been opened by movement of the lever 233 beyond full throttle as described in the preceding paragraph. Closure of the valve 260 yat all normal output shaft cruising or road load Vspeeds is desired because high torque multiplication is not needed and in order that the consequent low angle positioning of the stator blades will then offer a minimum impedance to the toroidal flow of the converter-fluid in either direction between the turbine T-2 and the impeller I, with the result that the tightest possible uid coupling action (condition of minimum slip) between these elements will be obtained.

Refem'ng again to the turbine-control-fluid pressure regulating valve 246, this valve may be maintained in its kopen position shown during engine idling by a spring 272 acting through a piston 271 and pin .273 to apply suicient force for that purpose on the piston 274, spring 247 and pin 275. Under these conditions, full main line pressure 'from the passage 221, valve 246, line 245 and supply pipe 84 acts against the piston valve 99 (FIG URE 1) and the T-l turbine blades are held in their maximum angle position shown in broken outline 4 in FIGURE 23. Pressure for moving the piston 271 against the spring 272 to allow the turbine blades to pivot to an intermediate angle position when the manual control lever 233 is moved away from its minimum speed setting position, is provided by the passage 276 which connects through the branch passage 262 with the main line pressure passage 221 when the follower valve 261 is initially moved to the right from its position as shown. With main line pressure acting through the passage 276 against the piston 271 in this manner tht force of the spring 272 is relieved from the valve 246 and the latter is permitted to reach its self-registering position corre sponding to the biasing force of the metered line-pressure in the line 240 and the governor controlled pressure in the line 242. As is known in the art, whenever the valve 246 is open, duid Hows from main line 221 into the chamber between lands 286 and 286a and through the passage through land 286:1 shown in dotted lines in'FIGURE 24.

Pressure on the left Vhand 28611 urges the valve to the right, 'and when the forcev of this pressure exceeds the sum of the forces tending to move the valve to 'the left, the valve closes vby moving to the right, closing the entry from line 221 and uncovering the :low pressure lubricating line 287 to relieve excess pressure. Relief of excess pressure lets the valve open again. This reduces the pressure on the left of land 286a so that its force is less than the sum of the opening forces (namely the Aforce of governor pressure on piston 286, .the spring 247 and throttle pressure on piston 274). This closes the relief line and again adrni-ts uid from the main line. Thus the valve alternates or hovers between two positions, one in which the entry port from main line 221 is slightly open and the relief line 287 is closed, and the other in which 'the main line is closed and the relief -line is Vslightly open. This maintains in the turbine control yline 245 andthe turbine control cylinder 76a a pressure which ismeasured by the sum of the opening forces on the valve 246, which forces increase with throttle opening, as has Ybeen-explained.Y

Thus it will be seen that with both the stator control valve 260 maintained in its open position by the spring 277 and the turbine control valve 246 maintained vopen by the spring 272 while the manual controlled lever 233 is in its minimum speed setting position, the effect vof both high angle stator blade pitch and maximum angle turbine blade pitch is obtained to resist vehicleV creep at idle. If it be considered unnecessary in the application Vof this transmission to a particular vehicle that both of these anti-creep features be incorporated, the passage 276, together with its associated piston v271, spring 272 and pin 273 may be omitted, in which case only the high angle blade setting of the stator will be effective at idle for Vthis purpose. Alternatively, 'the connecting passage 280 to the stator control valve 260 from the line 262 may be omitted and the right hand end of the large pis- -ton portion 268 be subjected to main line pressure in line 221 rather than to governor controlled pressure in line 242 as shown.. With this latter arrangement, the stator blades will remain in their low angle position until the manual con-trol lever 233 is moved to its maximum speed setting position, resulting in main line pressure being applied to the piston 281 and driving this valve 260 to the open position shown in FIGURE 24. f

Since it is also desired for tight coupling action that the turbine T-1 oder a minimum impedance to the ilow of converter-duid between the turbine T-2 and impeller I during normal road load operation, suitable means is provided for maintaining the turbine-control-iuid pres sure regulating valve 246 in its fully closed position under such conditions, so that the turbine T-1 blades will be in their minimum angle position. This is accomplished as shown in FIGURE 24 by providing for the governor controlled pressure to act on a piston 283 through a pin 284 to drive the valve 246 to its closed position when the output shaft speed reaches a road load value corresponding to any particular setting of the manual lever 233. The spring 285 prevents the .piston 283 from acting on the valve 246 at low carV speeds, that isuntil the force of governor pressure overcomes the spring 285. Thereafter movement of the piston 283 is resiliently opposed by the spring. The rate of the spring 285 and the area of piston 283 are so proportioned to the rate of spring 247 and areas of pistons 286 and 274 that closing of the valve 246 occurs whenever the resultant force of the governor control pressure on the valve 246 reaches a value suicient to overcome the opposing force of metered line pressure in the passage 240.

In order that the turbine-control-fluid delivery passages to the valve 99 (FIGURES l and 2) aliorded by the supply piper84, output shaft 6 and line 245 (FIGURE 24) will be maintained full when the valve 246 is held closed by governor controlled pressure as described in the preceding paragraph, the piston portion 286 of valve 246 is arranged` to open the Vline 245 -to the lubrication line 226 by branch line 287. By thus maintaining a charge of fluid in those passages at a relatively low pressure (insucient to aifect the blade pitch of turbine T-l) while the valve 246 is closed, a quick response to increased speed settings of the lever 233 is obtained when valve 246 is moved to the left, again establishing cornmunication between pump supply line 221 and the turbine control uid line 245.

From this description of the transmission and control system it will be observed that the driving input torque delivered by the impeller is so transmitted through the rst and second turbines T-1 and T-2 and through the gearing to the transmission output shaft 6 that the acceleration of the latter under load is gradual and smooth, even during shift of ratio in the gearing. Efficient torque conversion is also obtained `throughout each range of output shaft speed before and after this change in the T-l turbine drive ratio is effected by reason of the fact that the blade pitch angle of the turbine T-l is gradually increased in each instance as the turbine T-2 assumes its greater share of the load. By providing the means for increasing the blade angles of the stator above full throttle, the torque multiplication of the entire transmission can be increased which is desirable in obtaining maximum acceleration of the vehicle. Also, improved coupling efliciency of the converter at vehicle cruising speeds and effective anti-creep under idling conditions are realized.

Rsum of operation Engine idling-Referring to FIGURE 24, if the engine is idling with the throttle closed and the car is standing, the pump 21 supplies oil at standard line pressure through main line 221 to the inlet of the throttle pressure valve 228, which because its spring 239 is under minimum stress, regulates to provide minimum throttle pressure in the chamber between the lands 234) and 231 and in the throttle pressure line 240. There is no governor pressure on piston 232 in the throttle pressure valve because governor line 242 is vented through the valve 244 of the stationary governor 243, by way of the governor exhaust port EX.

The throttle follower valve 261 is held in the position shown in FIGURE 24 by the throttle link 233 so that its land 265 closes entry from the main line 221 and vents line 267 from the stator control valve 260 at vent port EX. This prevents closing pressure on piston 281 of the stator control valve. Also, conduit 262 is vented at the open left end of the throttle follower valve 261 adjacent its land 266, and this prevents pressure on the right of a hydraulic detent formed by free piston 263 in the throttle follower valve, vents opening line 280 of the stator control valve to prevent opening pressure at the right of stator control valve 264), and vents line 276 from the turbine control valve 246, prevent-ing pressure on the spring control piston 271 in that valve.

This leaves the stator control valve 260 opened by spring 277, there being no governor pressure on piston 268 which would tend to close the valve. The open stator control valve `260 fills the high angle stator holding chamber 178--179 (FIGURE 2) at main line pressure, and this overcomes converter pressure on piston 172 and holds the stator vanes at high angle to prevent creep.

It also leaves the spring 272 of the turbine control valve free to hold open that valve through pin 273, piston 274, spring 247 and pin 275. There is no governor pressure on pistons '283 and 286 and the throttle pressure on piston 274 is low. The turbine control valve 246 now maintains full main line pressure in turbine control line 245 and in the turbine high angle holding chamber 76a (FIGURE 2) which holds the turbine blades at maximum angle 'to/prevent creep.

'I'he gear shift valve 248 is closed by spring 250 against minimum throttle pressure on the right of the valve. This prevents uid from entering the valve from main line 221 and vents the supply line 223 of the sun 18 gear brake cylinder 216 (FIGURE 1a) so that the sun gear 203 can rotate backward. This conditions the transmission for low speed ratio or high torque ratio drive Whenever the car is subsequently started.

Starting the can- Referring to FIGURE 24, consider that the throttle has been opened slightly so that the throttle follower valve 261 has moved slightly to fthe right of the position shown in FIGURE 24. Its land 266 now closes the open left end of the throttle follower valve chamber and its land 265 has opened the entry port from the main line 221. Conduit 267 remains vented as when the engine was idling, and thus vents the opening chamber at the left of piston 281 of the stator control valve 260. Conduit 262 conducts oil from the throttle follower valve chamber by line 280 to the closing chamber at the right of stator control valve 260. This closes this valve against the spring 277, venting the high angle stator holding cylinder 178-179 (FIGURE 2) and placing the stator blades 148 in the low angle position shown in full lines in FIGURE 23. Also, oil at main line pressure from conduit 262 urges the throttle follower valve detent or piston 264 to the left. This provides a resistance against inadvertent kick-down as will be explained. Oil from conduits 262 and 280 also pressurizes conduit 276 and exerts pressure on piston 271 of lthe turbine control valve, compressing spring 272 and removing its force from the turbine control valve 246. This leaves the turbine control valve free to regulate the pressure in the turbine control conduit 245 and turbine control chamber 76a (FIGURE 2) at a value measured by the throttle pressure. Opening of the throttle has increased slightly the throttle pressure in line 240 and on the piston 274 of the turbine control valve 246 which adds opening force to the valve 246. This opening force at this low value of throttle pressure is less than the opening force on the valve formerly exerted by spring E272 when the space at the left of piston 271 was vented, and since this pressure is low the turbine control valve now maintains a low pressure in the turbine high angle holding chamber 76a and this lets converter pressure hold the turbine blades at low angle.

Under the conditions just described, the engine exerts suicient torque through the torque converter and gearing to start the car against low resistance, for example, when the car is on level ground. The stator blades and T-1 blades are at lowest angle and the planetary gear is in thev highest torque ratio. The amount of `torque delivered by the torque converter is regulated by the amount of throttle opening. Increase in throttle opening increases throttle pressure and this increases the force on the piston 274 in the turbine control valve 246 to increase `the angle of the turbine blades with increasing torque demand.

Sudden stam-The car may be started with both high turbine angle and high stator angle by flooring the throttle pedal. When this occurs the linkage 233 moves the throttle follower valve 261 fully to the right and moves the piston or detent plug 263 fully to the right. This vents the stator valve closing chamber on the right of the valve stem 260 and pressurizes the opening chamber on the left of piston '281 which assures opening of the stator control valve and pressurizes the high angle stator holding chamber 178-179 to put the stator blades at high angle. It also removes pressure from the spring-holding piston 271 of the turbine control valve 246 so that the spring 272 holds the valve 246 wide open to deliver maximum turbine control pressure or line pressure lto place the turbine blades at maximum angle. This starts the car Iwith the torque converter `delivering its maximum torque multiplication. After the car has attained some predetermined high speed, the governor pressure in the stator control valve 260 can close the valve to return the stator blades to low angle.

I-t may be undesirable to use this maximum torque multiplication in low gear ratio. It is noted that maximum throttle pressure in the opening chamber at the 19 right of the stem of the gear shift Valve 248 opens this valve against the closing lspring 250 to brake the sun gear 203 against reverse rotation and place the planetary gear set in high speed ratio.

Assuming a normal start, as the car begins to move, the governor 243 generates pressure measured by the speed ofthe car in the governor line 242 and all control chambers connected to it. In the throttle pressure valve 228 this governor pressure on piston 232opposes the spring 239 and assists throttle pressure in the line 240 in urging the throttle valve 228 closed. This decreases the throttle pressure in accordance With increase in car speed. Decreased throttle pressure reduces pressure in the turbine high angle holding chamber 76a-79. Since oar speed is proportional to the speed of the second turbine T-2, this tends to reduce throttle pressure and first turbine blade angle as the speed yof the second turbine increases. However, this tendency is opposed by governor pressure acting directly on land 286 of the turbine control valve, which increases turbine control pressure and blade angle of turbine T-1 as the speed of T-2 or the speed of the car increases. It is noted that governor pressure is also exerted on the left of piston 283 of the turbine `control valve which can act on rod 284 to increase the closing force on turbine control valve 246 and thus reduce the control pressure and T-l blade angle as car speed increases. It will be remembered that oneof the objects of the invention is to increase the turbine angle with increasing speed of the car or of second turbine T-Z. To permit this to occur within a limited range of speed the piston 283 is prevented from moving under the influence of Vgovernor pressure by a heavy spring 285 until a predetermined car speed is reached. When such high speed is reached the piston 283 overcomes the spring 285 and the larger area of the piston 283 exerts a larger closing force on the valve 246'than the opening force exerted on the valve by the governor pressure yagainst the smaller piston 286. Thus above a predetermined car speed the turbine control valve is closed so that the pressure in the turbine control chamber 76a is reduced to minimum and the blades are returned to lowest angle.

High gema-The car startswith the planetary gearset in high torque or low speed ratio unless the throttle is opened far enough to push the detent piston 263 to the right in FIGURE 24.

As car speed increases, governor pressure exerts increasing force on the piston 252 of the gear shift valve until at somey predetermined speed the spring 251 is stressed enough to open the gear shift valve 248, admitting oil at main line pressure from main line 221 to the conduit 249 to set the brake 219-220 to hold the sun gear 283 against reverse rotation. This changes the speed adds a closing force to the valve 246 and reduces the turbine control pressure, reducing the angle of the turbine blades. Thus, the turbine blades are maintained at a lower range of angular position when the gearing is in high speed ratio than when it is in low speed ratio.

The condition just described can be maintained overY various throttle openings up to full throttle, it being borne in mind that increasing torque demand, evidenced by increasing throttle opening, increases the throttle pressure which tends to increase blade angle of the turbine up to a particular throttle opening as determined by theV skirt of thepiston'274, and increasing car speed tends both to reduce throttle pressure and also tends to increase turbine control pressure and has the net etect of increasing the angle of the blades of T-1.`

Kick-down.-During all operations from slightly open throttle to full throttle, the high anglehold cylinder 179 of thestator is vented by the stator control valve 260VV which is held closed by pressure of the main line in the closing chamber at the right of that valve, so that the stator is at low angle. At full throttle the right end of the stem of the throttle follower valve 261 just touches the piston 263, which resists further movement because line pressure urges it toward the left. In response to very high torque demand, the throttle control mechanism is moved past wide-open throttle position by the operator and this pushes the piston 263 fully to the right against the end of the valve casing. Inadvertent movement of the throttle control past wide-open position is prevented by the pressure on the right side of piston 263 which must be deliberately overcome by the operator in forcing the throttle follower valve further to the right. When the throttle follower valve and piston are moved to the right as far as they will go, the land 266 is at the right of conduit 262 which is now vented through the open left end of the throttle follower valve. This vents conduit 276 and removes pressure from the piston 271 in the turbine control valve, allowing the spring 272 to exert opening force on the turbine control valve 246 to increase the angle of the turbine blades. This causes the turbine to deliver greater torque. Simultaneously, the conduit 280 'and the closing chamber at the right of the stator control Valve 260 are vented, and the opening chamber at the left of the piston 281 is charged at main line pressure from the line 267 which now is between lands 266 and 265, the latter of which blocks the exhaust port EX. This closes the stator control yvalve 260 provided the car speed is below a predetermined value, as will be explained, and moves the stator blades to high angle to provide further increase in torque multiplication in the torque converter.

`It is noted that the governor pressure on the right of piston 268 opposes the valve opening force of main line pressure on piston 281. At some predetermined high value of speed, governor pressure can overcome main line pressure on the stator control valve and again closes the valve to place the stator in low angle. However, this leaves the turbine control valve undisturbed, and it continues to hold the turbine blades at high angle, unless the speed is of such value that the governor chamber adjacent piston 2813 overcomes the governor chamber adjacent land 286, in which case, as explained above, the angle of the turbine blades will be reduced.

While the invention has been described and shown with reference to a preferred structural embodiment, this should be considered in its illustrative and not in a limiting sense, since it is appreciated that various changes may be made therein without departing'from the scope and spirit of the invention as now to be claimed.

This application is a continuation of my application Serial Number 328,090, tiled December 26, 1952, now abandoned.

What is claimed is:

l. A transmission comprising a stationary casing, a hydraulie torque converter having impeller, turbine and reaction Wheels, each wheel being rotatable with respect to the casing and each including a series of circumferentially spaced fluid guiding blades and a blade support, said reaction wheel having its blades pivotally mounted in its rotatable support'and having a blade shifting member rotatable relative bothto the casing and to the reaction blade support, said blades of the reaction Wheel having portions interengaging said shifting member such that rotation of said shifting member relative to said reaction blade effects pivotal movement of its blades relative to the reaction blade support, a cylinder formed'by said reaction blade support, a piston slidably tting said cylinder, interacting cam surfaces on said piston and on said blade-shifting member adapted to rotate the blade-shifting member when the pistonV is moved axially within the cylinder, and'means for introducing fluid under pressure from said 'stationarycasing to said rotatable cylinder to displace said piston and thereby rotate said shifting member and pivot said stator blades relative to their support.

2. A transmission comprising a hydraulic torque converter having rotatable impeller, turbine and stator wheeis, each including a series of circumferentially spaced fluid guiding blades and a support, each of said turbine and stator wheels having its blades pivotally mounted in its support and each having a blade shifting member rotatable relative to its support, and separate fluid pressure actuatable members for rotatively moving said blade shifting members relative to their respective support, one of said iluid pressure actuatable members being rotatively coupled to its blade shifting member and having cam surfaces adapted to engage cam surfaces on its associated support to rotate the blade shifting member with respect to its support when the blade shifting member is moved axially, the other of said fluid pressure actuatable members being rotatively coupled to the support and having cam surfaces adapted to engage with cam surfaces on its associated blade shifting member to rotate the blade shifting member when said other fluid pressure actuatable member is moved axially.

3. A transmission comprising a hydraulic torque converter having rotatable impeller, rst turbine, second turbine and stator wheels, each including a series of circumferentially spaced blades extending between inner and outer supports, concentric relatively rotatable torque transmitting tubes having flanges coupled to the outer supports of the rst and second turbine wheels respectively, said first turbine Wheel being interposed between the impeller and second turbine wheels and having its blades pivotally mounted on its supports for varying the torque absorption of the first turbine wheel relative to the second turbine wheel, a blade shifting ring journalled to the outer support of the iirst turbine wheel and pivotally connected to each of the rst turbine blades, a cylinder member reciprocably and rotatably mounted on the inner tube flange, an axially yieldable rotatively rigid disk coupling said cylinder member to said ring, a cam fixed to said inner tube ange having helical cam surfaces, rollers journalled in said cylinder member and engaging said cam surfaces, means for introducing uid at controlled pressures into said cylinder member to shift the same axially of said inner tube, said means including a Huid supply pipe extending longitudinally through said inner tube and defining an annular Huid return passage therebetween, a Valve body within said inner tube having inlet and outlet ports communicating respectively with the interior of said pipe and said annular return passage and having a common inlet and outlet port communicating with the interior of said cylinder member, a self-registering piston -valve reciprocably mounted in said body and responsive to iiuid pressure in said pipe controlling said ports, and a resilient member urging said valve to a position closing said inlet port but yieldable in response to fluid pressure in said pipe to sequentially close said outlet port and open said common inlet and outlet port, and a reaction member for said resilient member recipro` cable with said cylinder member.

4. A transmission comprising a housing, a hydraulic torque converter having a rotatable impeller, a rotatable turbine in direct uid receiving relation with the impeller, said turbine having spaced iiuid guiding blades and inner and outer supports dening the ends of the interblade spaces, pins interconnecting the supports and journalling the blades for rotation between the supports, a ring rotatable coaxially of the turbine and pivotally connected to each of said blades about axes laterally spaced from the axes of said pins, a disk rigidly connected to one of the supports, a tubular shaft having an enlargement at one end terminating in a flange fixedly secured to the disk, a cylinder slidably embracing the periphery of the flange and the periphery of the enlargement, an axially yieldable member rotatively coupling said cylinder to said ring, a plurality of circumferentially spaced rollers journaled in the cylinder for rotation about axes disposed radially of the cylinder, a'cam ring rigidly connected to the ange having helical slots engaging the rollers, a generally cup-shaped valve body seated within the enlargement having its open end facing the opposite end of said shaft, a uid supply pipe extending concentrically of said shaft and litting the open end of said body, said pipe and shaft defining an annular fluid return passage therebetween, said body and enlargement having connecting ports communicating with the interior of the cylinder and said body having other ports communicating respectively With said return passage and the interior of said pipe, a piston valve slidably reciprocable in said body and controlling the opening and closing of said ports, said valve being movable in response to uid pressure in said pipe to sequentially block communication between said return passage and the interior of the cylinder and to open communication between the interior of the cylinder and the interior of the pipe, a spring supported by the cylinder and resiliently opposing movement of the valve in response to iluid pressure in the pipe.

5. A transmission comprising a housing, a hydraulic torque converter having a rotatable irnpeller, rotatable iirst and second turbines in successive iluid receiving relation with the impeller and a one-way rotatable stator in fluid receiving relation with the second turbine, said first turbine and stator each having blades shiftable from a low angle to a high angle fluid receiving position, an output shaft coupled to the second turbine, a multi-speed gearing system for drivably connecting the first turbine to the second turbine at different predetermined speed ratios, and control means including a manually controlled member movable between low and high speed setting positions and a governor responsive to output shaft speed conjointly operable to -shift said first turbine blades toward their high angle position to the extent necessary to maintain a driving connection between said first turbine and the output shaft in each gear ratio and to shift said stator blades from their low angle to their high angle position in response to moving said manually controlled member a predetermined extent toward its maximum speed setting.

6. A transmission comprising a supporting housing, a hydraulic torque converter, a planetary gear system and an output shaft driven by the gear system, said torque converter including an impeller, a first turbine having variable pitch blades in direct iluid receiving relation with the impeller and a second turbine in direct fluid receiving relation with the iirst turbine, said gear system including first and second annulus gears coupled respectively to said iirst and second turbines, first and second planet gears meshing with the respective first and second aunulus gears, a common sun gear meshing with both said first and second planet gears, a carrier for said irst planet gear coupled to said output shaft and to said second annulus gear, and a carrier for said second planet gear, a one way brake locking said rsecond planet gear carrier to the housing against rotation in the direction negative to the drive, a fluid pressure actuated brake for releasably locking said sun gear to the housing against rotation in the direction negative to the drive, a iiuid pressure actuated member controlling the blade pitch of said iirst turbine, a source of iiuid pressure and means for controlling the application of said uid pressure to said pressure actuated brake and member in response to the speed and torque demands of said output shaft, said controlling means including an output shaft speed responsive governor, a manually movable member, and a fluid pressure regulating valve conjointly controlled by said manually movable member and said governor.

7. A transmission comprising a stationary housing, a hydraulic torque converter including a uid-couning shell rotatably supported in said housing, an input shaft drivingly connected to said shell, concentric radially spaced sleeves dening a passage therebetween for converter-fluid entering the shell, the inner of said sleeves being xed to the` housing and the oute'rof ysaid sleeves `being rotatable with the shell, aconverter-fluid supply pump having a pump body xedly connecting said inner sleeve to the housing and a rotor driven by the outer sleeve, rotary impeller, turbine and stator units in fluid circulating relation with the shell, each having a plurality of circumferentially spaced blades between inner and outer supports, said irnpeller unit being rotatable with the shell, a tubular shaft driven by the turbine unit and extending coaxially through `said inner sleeve, said shaft and inner sleeve having a clearance space therebetween, said stator unit having its blades pivotally mounted in supports, said stator unit having yits outer support rotatably supported by said shaft and sleeves and having one-way brake means engageable with said inner sleeve to prevent rotation of the stator unit oppositely of t-he impeller unit, said stator unit outer support having a circular recess with concentric side walls forming an annular cylinder open at one end to the interior of said shell and communicating at its opposite endwi-th said clearance space, an annular piston reciprocably guided in said cylinder for axial movement in response to the respective pressures in said shell and clearance space, a cam member journalled by the stator unit outer support and pivotally connected to each of the stator blades, said cam member and piston having interacting cam surfaces adapted to rotate the cam and piston relative to each other when they are moved axially relative to each other, and manually controlled means for `connecting said clearance space to iuid pressure delivery from said pump whereby the pitch of the stator unit blades may be adjusted to vary the torque transmitted from the impeller unit to the turbine unit.

8. A transmission comprising a hydraulic fluid coupling unit including a rotary uid driving impeller, a first turbine in direct iiuid driven relation with the impeller having blades adjustably movable through a range from low to high angle pitch positions, a iiuid pressure movable blade angle adjusting member for said rst turbine, means yieldable biasing said member to its low blade angle adjusted position, a second turbine in direct iluid receiving relation with said first turbine, gear means limiting the maximum rotating speed of the rst turbine relative to the speed of the second turbine, a source of fluid pressure, passage means for conducting fluid under pressure from said source to said member, and means responsive to the rotating speed of the second turbine for controlling the fluid pressure in said passage means whereby the pitch `of said rst turbine blades is increased with increasing speed of rotation of said second turbine to maintain the speed of the rst turbine at said maximum relation to the speed of the second turbine.

9. A transmission, comprising a hydraulic iiuid coupling unit including a rotary uid driving impeller, a iirst turbine in direct fluid driven relation with the impeller having blades pivotally adjustable through a range of low, intermediate and high angle pitch positions and a second turbine in iiuid receiving relation with the iirst turbine, a blade pivoting member rotatably mounted on said iirst turbine, a uid pressure movable memberrrotatable with said blade pivoting member and movable axially and rotatably with respect to said iirst turbine to effect blade pivoting rotational movements of said blade pivoting member relative to said iirst turbine, means for applying controlled uid pressure to one side of said pressure movable member to move it axially with respect to the iirst turbine, inner engaging cam surfaces on said pressure movable member and said first turbine to rotate the pressure movable member with respect to the turbine in response to axial movement and thereby to cause pivoting of the iirst turbine blades from their low angle position toward their high angle pitch position, and biasing means yieldably opposing movement of said pressure Y movable member in said direction.

l0. A transmission comprising a hydraulic fluid couplingunit including a rotary driven impeller, a first turbineY in `direct fluid driven relation wi-th theimpeller having blades adjustably movable through a rangev from low to high angle pitch positions and a second turbine in uid receiving relation with said rst turbine, a fluid pressure movable blade adjusting member for the iirst turbine, means resiliently biasing said member to its low blade angle adjusted position, gear means drivingly connecting the second turbine to the iirst turbine at predetermined high and low speed ratios corresponding to respective high and low maximum speeds of the iirst turbine relative to the second turbine but accommodating rotation ofthe iirst turbine relative to the second turbine at less than said ratios, iiuid pressure actuable means for changing the speed ratio of said gear means from high to low, means yieldably opposing actuation of said pressure actuable means to its low speed ratio condition, a source of uid pressure applicable to move said member from its low blade angle position to its high blade angle position and to actuate said pressure actuable means to its low speed ratio position, and means responsive to the rotating speed of the second turbine for controlling the application of said pressure to said member and actuable means whereby during rapid acceleration of 'the i-mpeller relative to the second turbine the pitch of said turbine blades is increased gradually toward their high angle setting with increase in speed of the second turbine to a predetermined value while said `gear means is maintained in its low speed ratio, and thence said turbine blades are returned to a lower angle setting substantially simultaneously with a shift of said gear means to its low speed ratio, and thence said turbine blades are again gradually moved toward their high angle setting with continued increase in speed of said second turbine.

11. In a transmission, a hydraulic torque converter comprising rotary impeller, turbine and stator elements in fluid circulating relation, a stationary housing, a shell enclosing the converter and rotatable with the impeller, an outer/sleeve `journalled in the Vhousing and radially supporting/the shell at one end of the converter, said outer sleeve having ya flange securing thevimpeller to the shell and locating the stator in one axial direction, an inner sleeve extending coaxially through the outer sleeve and having its end outwardly of the converter fixed rigidly to the'housing, a turbine driven shaft extending coaxially through said inner sleeve and terminating inwardly of the shell with a flange secured to the turbine and locating the stator in the opposite axial direction, said stator having variable pitch iiuid guiding blades and a support pivotally supporting the inner ends of the blades, a one-way brake preventing rotation of stator oppositely of the impeller including an outer race member journalled on said inner sleeve and iixed to said support, said support having an annular recess constituting a uid pressure cylinder, an annular pis-ton fitted in said cylinder and guided for reciprocation longitudinally of the converter axis, a ring interconnecting the'stator blades and journalled on said support,'said`ring and piston having interengaging portions eiecting oscillatory rotation of the ring in response to reciprocation ofthe piston, and means for supplyinghydraulic uid under pressure for ow between said sleeves und into the converter shell and for flow between said inner sleeve and said shaft into said cylinder.

- l2. In a transmission, a hydraulic torque converter comprising a stationary casing, a rotatable Vreaction stator having spaced iluid guiding blades and a blade supporting means rotatable with respect to the casing, said blades being adjustably movable relative to the rotatable supporting means to different angular pitch relations to the direction of the driving fluid entering the inter-blade spaces of the stator, 'and means for adjustably moving said blades including a fluid pressure actuatedrpiston rotatable with respeot to the casing, rotationally iixed with respect to the blades supporting means and axially shiftable relative to the supponting means, a blade interconnecting member rotatable relative tothe supporting means, a blade intercon- 

